Laser
Direct Writing of Flexible Sensor Arrays Based
on Carbonized Carboxymethylcellulose and Its Composites for Simultaneous
Mechanical and Thermal Stimuli Detection
posted on 2021-02-16, 17:11authored byQi Li, Ruijie Bai, Yang Gao, Rongyao Wu, Kuan Ju, Jianping Tan, Fuzhen Xuan
Multifunctional
sensing devices with high flexibility, high sensitivity,
and scalable fabrication are inevitable components of Internet of
Things (IoT) for human–machine interfaces, structural health
monitoring, and soft robots. Herein, high-performance flexible sensor
arrays using carboxymethylcellulose (CMC) and its composite were developed
for mechanical and thermal stimuli detection by laser direct writing.
CMC contains abundant carbon precursors for strain-sensitive laser-carbonized
CMC (LC-CMC), while the incorporation of graphene oxide (GO) into
CMC leads to the formation of thermal-sensitive laser-carbonized GO/CMC
(LC-GO/CMC). The LC-CMC-based strain sensor delivers gauge factors
of 487.7 (strain < 8.5%) and 8557 (8.5% < strain < 14%),
with long-term stability over 10 000 cycles. With 0.2 wt %
GO, the LC-GO/CMC-based device provides a temperature coefficient
of resistance of −0.289% °C –1, higher
than the Cr-based commercial sensor. The potential application of
the devices in IoT is proved by combining the near-field communication
technology with the LC-CMC-based device to monitor the strain suffered
by 316L stainless steel during the fatigue test. Moreover, an integrated
device based on the strain and temperature sensing arrays accomplishes
the simultaneous measurement of temperature and mechanical deformation
in real time.